This is a digital thermostat. You can set the temperature to match the on/off state of the lighting. I liked the black body of this one. It's an old item, but I used it for about a year. I'll include suction cups that are stronger than the original ones (see photo). There are no instructions or box, but I'll include an explanation of the switches in the photo section. You should be able to find them by searching online. Compared to the LCD type, the illuminated digital type like this one is easier to see, and the settings are simpler with fewer button presses. I bought several new ones about seven years ago, intending to use them for a long time, but since I managed the room temperature with air conditioning, they were hardly ever used. I am a non-smoker, and I didn't have any pets other than reptiles. [Note] I had it fixed to a pillar, so I shaved off four small protrusions on the back of the case (see photo 3). Please refrain from purchasing if you are concerned about the condition. Thank you for looking.